Passenger seats of automobiles or trains, various kinds of sofas, office chairs and the like are often formed by attaching a skin material such as fiber fabric or natural or synthetic leather to the surface of a cushion body (foam body) molded in a predetermined shape by using a foam resin material. The cushion body used in these various seats often has a curved surface composed of convex-concave shapes satisfying human engineering factors in order to maintain a seating posture which provides no fatigue despite long-hour seating.
Moreover, when the skin material is attached to the surface of a cushion body, after molding the cushion body in a desired shape, a method of covering and fixing the skin material to the surface of the obtained cushion body is often employed. In particular, in this case, a molded surface fastener is generally used as means for fixing the surface of the cushion body and a back surface of the skin material.
A molded surface fastener has a configuration in which a plurality of engaging elements (for example, male engaging elements) are disposed on one surface (first surface) of a base portion made of a thermoplastic resin, and such a molded surface fastener is integrated so that the engaging elements are exposed to the surface of the cushion body when the cushion body is molded. Moreover, a plurality of female engaging elements configured to be fastened to the engaging elements of the molded surface fastener are formed on the rear surface of the skin material that covers the cushion body.
After the skin material is covered on the cushion body to which the molded surface fastener is integrated, the female engaging elements (loop-shaped engaging elements) disposed on the back surface of the skin material are pressed against the male engaging elements of the molded surface fastener disposed to the surface of the cushion body, whereby the skin material is fastened to the molded surface fastener. In this manner, the skin material is easily fixed to the surface of the cushion body along the convex-concave shapes of the surface, and the skin material is prevented from floating from the cushion body.
Such an example of the molded surface fastener integrated to the cushion body to fix the skin material is disclosed in International Publication 2012/025980 (Patent Document 1) and the like.
For example, a molded surface fastener 80 described in Patent Document 1 has, as shown in FIG. 35, a long and flat plate-shaped substrate portion 81, left and right barrier portions 82 disposed on left and right side edge portions of the substrate portion 81, a plurality of hook-shaped engaging elements 83 disposed between the left and right barrier portions 82, a magnetic material holding portion 84 disposed inside the barrier portion 82, a lateral wall portion 85 disposed along a width direction, and fin piece portions 86 extending from the left and right side edges of the substrate portion 81 toward the outside in the width direction. Moreover, a linear magnetic material 87 is integrally molded to the molded surface fastener 80 in a state to be held by the magnetic material holding portion 84 along a length direction.
The engaging elements 83 in Patent Document 1 are disposed at a predetermined pitch in a line in the length direction (a fastener length direction) of the substrate portion 81, and the five lines of the engaging elements 83 are arranged in the width direction. Moreover, each engaging element 83 has a raising portion erected from a surface of the substrate portion 81 and a hook-shaped engaging head portion (hook portion) curving and extending toward front and rear in the fastener length direction at an upper end of the raising portion, and is formed as a so-called male engaging element 83.
The left and right barrier portions 82 have three lines of vertical wall portions disposed along the length direction and connecting portions connecting between the adjacent vertical wall portions. Each line of vertical wall portions has a plurality of vertical wall bodies disposed at a predetermined pitch intermittently in the length direction. Each vertical wall body has a post portion erected from the substrate portion 81 and an upper surface portion disposed on an upper end of the post portion. Each upper surface portion is formed so as to hang over from the upper end of the post portion in the length and width directions.
Each vertical wall has such an upper surface portion, whereby in attaching the molded surface fastener 80 closely to a cavity surface of a molding die, the adhesion of the molded surface fastener 80 can be stronger by increasing the adhesion area between the vertical wall portion of the molded surface fastener 80 and the cavity surface of the molding die.
Such a molded surface fastener 80 in Patent Document 1 is manufactured by using a manufacturing apparatus 90, for example shown in FIG. 36.
The manufacturing apparatus 90 has a die wheel 91 rotated drivingly in one direction (the counterclockwise direction in the Figure), a continuous extrusion nozzle 92 which extrudes molten resin and is disposed opposing to a circumferential surface of the die wheel 91, a pickup roll 93 disposed on a downstream side of the continuous extrusion nozzle 92 in a rotation direction of the die wheel 91, a pair of upper and lower pressing rolls 94, 95 which are disposed on the downstream side of the pickup roll 93 and have a heating part, and a linear magnetic material supply part, not shown in the Figures, which is disposed on an upstream side of the continuous extrusion nozzle 92 in the rotation direction of the die wheel 91 so as to supply the linear magnetic material 87 between the opposing surfaces of the die wheel 91 and the continuous extrusion nozzle 92.
A cavity space 91a for molding the barrier portion 82, the engaging element 83, the lateral wall portion 85 and the magnetic material holding portion 84 of the molded surface fastener 80 is formed on the circumferential surface of the die wheel 91. Generally, the die wheel 91 is formed columnar by laminating a plurality of discoidal plates having a necessary thickness in a rotation axis direction of the die wheel 91. Further, a predetermined cavity space 91a corresponding to a position of a predetermined discoidal plate is formed on the peripheral part of that discoidal plate by electric discharge machining or laser processing.
For example, in the die wheel 91, the cavity space 91a corresponding to a form of the vertical wall portion is formed at a predetermined pitch in a circumferential direction on a peripheral part of a discoidal plate disposed on a position corresponding to the vertical wall portion of the barrier portion 82. Further, the cavity space 91a corresponding to a form of the engaging element 83 is formed at a predetermined pitch on a peripheral part of a discoidal plate disposed on a position corresponding to a row of the engaging elements 83 along the length direction. Then, the die wheel 91 is formed by laminating the plates of which the cavity space 91a are and are not formed on the peripheral parts in an axis direction in a predetermined order.
In a case of manufacturing the molded surface fastener 80 by using the manufacturing apparatus 90 having such a die wheel 91, the molten resin material is extruded from the continuous extrusion nozzle 92 continuously to the circumferential surface of the die wheel 91 in the first place. At this time, the die wheel 91 is rotated drivingly in one direction, and at the same time as the molten resin extruded to the circumferential surface of the die wheel 91 molds the substrate portion 81 of the molded surface fastener 80 continuously at the space between the continuous extrusion nozzle 92 and the die wheel 91, the barrier portion 82, the engaging element 83, the lateral wall portion 85 and the magnetic material holding portion 84 are molded in the above-mentioned each molding cavity serially.
In this case, the barrier wall portion 82, the engaging element 83 and the like are molded on the substrate portion 81 along a direction (hereinafter, a direction in which the molded surface fastener 80 is molded is referred to as “machine direction”) in which the molded surface fastener 80 is molded (i.e. along a length direction of the molded surface fastener 80). At the same time as the molten resin material is extruded from the continuous extrusion nozzle 92, the linear magnetic material 87 is supplied from the linear magnetic material supply part, not shown in the Figures, to the extrusion position of the molten resin and molded integrally to the molded surface fastener 80.
The molded surface fastener 80 molded on the circumferential surface of the die wheel 91 is solidified by making a half turn while being held on the circumferential surface of the die wheel 91 and cooled. After that, the molded surface fastener 80 is continuously peeled off from the circumferential surface of the die wheel 91 by the pickup roll 93.
Then, the molded surface fastener 80 peeled off from the die wheel 91 is carried between the upper and lower pressing rolls 94, 95. And an upper end part of the vertical wall body of the molded surface fastener 80 is pressed by the pressing rolls 94, 95 from the upper and lower directions, whereby a flat upper surface part is formed at the upper end of the post portion. Due to this, the molded surface fastener 80 of Patent Document 1 in which the engaging head portion (hook portion) of each engaging element 83 is formed along the fastener length direction as shown in FIG. 35 is manufactured.
On the other hand, for example in Japanese Patent Publication No. 2000-512174 (Patent Document 2), a method for manufacturing a molded surface fastener in which an engaging head portion (hook portion) of each engaging element is formed along a fastener width direction perpendicular to a fastener length direction is described as an example of methods for manufacturing a molded surface fastener.
Also in a case of manufacturing the molded surface fastener in which the engaging head portion has an engaging element in the fastener width direction, a die wheel which is formed by laminating a plurality of discoidal plates having a necessary thickness in an axis direction and a molding cavity molding the engaging element and the like on the circumferential surface is disposed on is used. In this case, since the molded engaging element is formed along a direction (hereinafter “machine intersect direction”) perpendicular to a machine direction (i.e. along a width direction of the molded surface fastener), a cavity space for molding one engaging element is formed over a plurality of discoidal plates of the die wheel.
For example, in Patent Document 2, the cavity space 99 for molding one engaging element is formed over plate a-plate k laminated each other at the circumferential surface of die wheel 98 as shown in FIG. 37. The cavity space 99 for one engaging element is formed over a plurality of plates a-k as above, whereby the molded surface fastener, in which a plurality of engaging elements in which the hook portion is directed to the fastener width direction are disposed on the substrate portion can be manufactured.